The objective of this Core Unit is to provide the investigators of the program project with a faculty allowing biological testing of the function of cloned hematopoietic stem cell genes. The facility is located in a microinjection suite on the -2 floor of the K wing of the UW Health Sciences Center of the University of Washington. It is fully equipped and has two microinjection units. A tissue culture room is located adjacent to this facility. The mouse rooms are located in the same area. The core unit has extensive experience in producing transgenic mice using plasmid or cosmid-sized constructs as well as with yeast artificial chromosomes (YACs). The personnel have experience with production of chimeric knockout mice. Core D will initially produce transgenic and knockout mice for Projects 1 and 2 and it will also be extensively utilized by Projects 3 and 4 once the genes responsible for familial leukemia or cyclic hematopoiesis have been cloned.